Its simple, graph them.
For the first equation, go on the Y-Axis (the vertical one) and go to 4. Then from there go up 1, right 6.
For the second equation go on the Y-Axis (the vertical one) and plot a point at 1 (aka 0,1) Now you go up 1, right 3.
When you see an equation like y=2x+3, the 3 represents the point (0,3) as when the x is 0, y=3. Just plug the numbers in. And as for the "2x" 2 is the slope. Slope is always rise/run or up, then right. So if its 2 your slope is 2/1, rise 2, over 1. If it "-2x" is your slope then all you have to do is go down 2, right 1.
I hope this cleared up your confusion, brainliest/heart would help.
Additional information to complete the question:
How long does it take for a short pulse of light to travel from one end of the glass to the other?
Express your answer in terms of some or all of the variables f and L. Use the numeric value given for n in the introduction.
T = ___________ s
Answer:

Step-by-step explanation:
Given:
Thickness og glass = L
Index of refraction n=1.5
Frequency = f

λ(air) 
λ(glass) = λ(air) / n
= 
= 
= 
V(glass) = fλ(glass)


Oh this is a hard one I will get back to you whenever I get it
It can be written as 12/100
or reduced to 6/50
or reduced even further to 3/25
The answer is 2.86 because you would divide 10 by 3.5